An organic electroluminescence device (hereinafter referred to as an organic EL device) has been recently adapted to applications such as a lighting panel and the like. There is known an organic EL device in which an optically-transparent first electrode (an anode), an organic layer and a second electrode (a cathode) are laminated on a surface of an optically-transparent substrate in that order, where the organic layer is formed of a plurality of layers and includes a light-emitting layer. In the organic EL device, by applying a voltage between the anode and the cathode, light generated in the light-emitting layer is taken out through the optically-transparent electrode and substrate.
In the organic EL device, a light quantity to be taken out is smaller than a theoretical light quantity in general because a light quantity from the light-emitting layer is reduced owing to absorption in the substrate, total reflection at an interfacial layer and the like. For example, in a case where glass is employed as substrate material, total reflection occurs at the interface and light-extraction efficiency is reduced because the glass has a refractive index lower than that of an organic layer in general. Therefore, what is needed in such an organic EL device is to increase the light-extraction efficiency for high brightness. It is conceivable that a substrate is formed of a composite substrate made of plastic member and glass member in order to increase the light-extraction efficiency. In this case, if the plastic member is disposed at a light-extraction side, total reflection at an interface between the substrate and an electrode is reduced. As a result, more light can be taken out.
Such a composite substrate can be also adapted to organic electric devices except for the organic EL device. Examples of an organic electric device include an organic solar cell, an organic display device (an organic display) and other organic semiconductor devices. In a case of the composite substrate, it is possible to obtain, according to an organic electric device, substrate material such as a composite substrate of a substrate suitable for improving a property of a multilayer (a multilayered body) and a substrate suitable for protecting the multilayer. In addition, a flexible substrate can be obtained by compounding flexible substrates.